I've noticed a similar phenomenon with my
SG-2100, but not so bad that I couldn't live with it. Particularly on G10R, some of the more marginal signals (the 11720 mux, of course) come in rock solid on one occasion, then on the next trip will be off just enough to require some
remote control "nudging" in one way or another. It's not consistently off in a particular direction. so I end up nudging it a notch or two in whatever direction it requires.
Mind you, in most cases the signal is good enough so that it's not an issue--if it's off slightly, so what?--but for the marginal ones, it
can sometimes be a pain.